Electric hammer



A g- 1932- s. M. DECKER ELECTRIC HAMMER Filed April 24, 1928 4 Sheets-Sheet l 15, s. M. DECKER 1,871,446

Filed April 24, 1928 4 Sheets-Sheet 2 INVENTOR ATTORNEY v am m Qedw/z/ Aug. 16, 1932. s. M. DECKER 1,871,446

ELECTRIC HAMMER Filed April 24, 1928 4 Sheets-Sheet s I: D a d W 56:1 7 U 55 .55 \d/ fil J T 53 54 \Nwjf J5 35 {IE5 CE: CED bNVEjTOR ATTORNEY S. M. DECKER ELECTRIC HAMMER Aug. 16, 1932.

Filed April 24, 1928 4 Sheets-Sheet 4 m QINVENTOR @m gqffiz I Patented Aug. 16, 1932 entree STATES w i I s'rrnns l mos Application fled April 84,

This invention relates particularly, though not exclusively to electrlc motors of the reciprocating type. v v V Special obJects of the inventionarej to provide a practical and efiicient motor construction for operating hammers, drills, pumps.

and other reciprocating types of. machines, and particularly one which will start and run on single phase alternating or pulsating ourrent without the aid of phase-sphttmg devices or other auxiliaries, which will have a high starting power, which can befcontrolled in its operation independently of the frequency of the energizing circuit, which will be, economical in current consumption and will be of simple, sturdy and inexpensiye construction.

The foregoing and other desirable ObJects are attained by utilizing in a practical way the electro-magnetic and electro-dynamlc forces resulting from primary and secondary windings on thetwo relatively movable members of the motor, arranged in inductive and magnetic relation and controlled to utilize the repulsive magnetic forces for efiectlng the de sired" movements. The invention involves also certain ,timin relations by WlllCh a dynamic braking ect is produced the reciprocating form of motor to 3}lSl11 0D. and start the reciprocating member of e motor on its return stroke, also in combination with the above, 5 ecial control means and are suppressing evices.

Various other novel features of the invention, constructions, combinations and relations of parts will appear as the specification proceeds.

The drawings accompanying and forming part of the specification illustrate one pract1-. cal embodiment of the invention, but it sh-juld be understood that the structure may be mouified and changed as regardsvthis parti'culai disclosure without departure from the. true spirit and broad scope of the invention as hereinafter defined and claimed.

' Fig. 1 is a perspective view illustrating one set .of the stator coils of the machine; Fig. 2 is a similar view showing the coils set in the stator and showing the movable ram in front so of the same; Figs. 3, 4 and 5 are front views PATENT" OFFICE. nnonitarimw m h i 1888-: 801'!!! I0. 2m". j 1 a". of the ram in the stator emanate showing respectively the ram inth jlewer starting position, the ram in the interfriediatei"n"eu,- tral? position, and the .theup'p'er position'at the start of'th'e down stroke. '1

F igs,' 6, '7 and 8 are views slir i l iirito Figs.

- 3, 4 and 5,;but showing the circuit and-contact control mechanism in. thefthree following positions: Fig. 6, ram on"down stroke at instant contactiis made for return'strok'e, Fig. I 7, ram approaching neutral on up-stroke, Fig. 8,,ram on up-stroke at instant circuit is closed for applying dynamic braking efiect, and starting it back on down stroke; Fig. 9 is a perspective view of the complete hammer;

ig. 10 is an enlarged cross-sectional view of the hammer structure as on substantially the lane ofline 10-10 of Fig. 9; Fig. 11 is a roken side elevation showing particularly 7 the anvil construction at the foot of the hammer.

In order that the structure and operation may be the more readily understood, the rangement of the stator or energizing ings is illustrated first in an elemental way, Fig. 1, and then as mounted in the stator and co-operating with the secondary winding of the ram or movable element.

Referring first to Fig. 1, each stator winding consists in the construction disclosed of pairs of coils 1-2, 3-4, 5-6, 7-8, with the coils of each pair connected in series in like relation, and the adjacent pairs connected in series in reverse relation. The coil units are shown as all alike, and consisting each of a fiat tape conductor wound on itself in rectangular form, and the coils of eachpair disposed side by side with the inner' end 9 of the first coil of a pair connected by a cross stra 10 with the inner end 11 of the second 0011 of the pair, and the outer end 12 of said second cord lapped over and connected with the outer end 13 of the first coil of the next pair, the coils ofadjacent pairs standing in reversely wound relation, so that these outer terminal ends stand in position to be lapped in this fashion.

With the construction described, the coils may all be wound alike, then bemade up in pairs by placing two coils side by side, but in reversely wound relation and connecting the inner ends of the two, so as to efiect a series cumulative relation. The .two coils thus con-' nected as a single unit may then be connected in relatively reversed relation with the next unit-connected pair of coils, the individual coils and coil units being suitably taped or otherwise properll y insulated after the manner indicated m ig. 2 in which the parallel end sections of the coils are -shown seated in slots 14, 15, 16, 17, 18 in the laminated stator structure 19. The direction of current flow is indicated by arrows in Fig. 1, from which it will be seen that with the terminal ends 20a, 21a connected in circuit, the flow of current through all the conductors in each slot will be in the same direction, and that the flow in adjacent slots will be in reverse directions.

In the form of construction disclosed, there are two stator elements 19, 20 placed opposite as in Fig. 3 with the ram indicated generally at 21 operating therebetween, and with the coils arran ed and connected as indicated in that view with the current flowing in the.

same directions in the slots at opposite sides of the ram, soas to roduce the cross-magnetic fields indicated y the flux lines 22.

The ram 21 is illustrated as a laminated magnetic body guided for reciprocation between the statorelements and carrying in the opposite surfaces of the same, copper, or other good conducting, bars 23 connected together at their ends by longitudinal bars 24 of copper, or other good conducting material, forming 'ds or secondary windings in inductive re ation to the stator .windmgs. The bars 23 of these grids are shown as spaced substantially in accordance with the spacing of the-stator slots. In practise, these grid bars may bezseated in holes drilled through the ram close to the surface of the same, but

if desired, these seats may be slots open to the opposite surfaces of the mm.

In the commercial embodiment of the invention illustrated more particularly in Figs. 9, 10 and 11, the stator or field laminations are secured together by cross welds 25, and

the two stator sections are secured together in properly spaced relation between side frames or plates 26 longitudinal bars 27 being shown interposed between the laminations and side frames to provide space 28 for the side portions of the coils, and welds 29 being shown for securing the stator laminations, spacers and side frames integrally together.

Positive guiding of the ram is efiected in ,the illustration by providing it with longitudinal ribs or flanges 30 on opposite sides sliding in guide grooves 31 on the inner sides of the frame plates. These guide flangesare shown as carried by the side plates 32 secured together by headed studs 33 and shouldered in their inner edges at 34 to overstand and protect the longitudinal and transverse grid ars.

The ram is shown as carrying a suitable hammer head 35 on its lower end secured integrally thereto bywelds 36 and as provided at its upper end with a welded-on cap piece 37.

The welding of the hammer head and cap piece to the body ofthe ram simplifies manutween component parts and this enables the ram structure to be built up in the laminated form, instead of solid as heretofore proposed. As a practical result therefore, the welding enables the use of laminations in that part of the ram which is subjected to fluctuating or alternating ma etic fluxes.

A loose anvi piece 38 is shown guided for vertical sliding movements in the lower end of the frame between guide plates 39 secured across bifurcated lower portions 40 of the side frames,these guide plates'being shown in Fig. 9 as extended out at the sides" of the frame plates to provide shoulders 41 on which rest the'stop bars 42. The anvil is shown. as having upper and lower flanges 43, 44 extending out over these stop bars, and whereby rtant for the reason that the ram it'is slldingly confined in the lower end of the machine. The. sto bars are shown as mounted by through bo ts 45, which further serve to brace and reinforce the lower end of the hammer. The lates 39 in addition-"to iding the anvil, a o aid in the placing of t e hammer over sheet piling or the like.

At the top, the side frames are shown as braced and connected by a top plate 46, which has an intermediate portion 47 extending down between the side frames and serving as a striker plate for the, ram head 38.

The handle 48 is shown provided on the top plate by which the hammer may be lifted and mani ulated. Protected by this handle, there is s own 'a plug 49 by which the operatin current is sup lied to the machine from t e conductor ca le 50, and a suitable switch for controlling the machine ma be incorporated in or associated with this andle or plug construction.

The hammer action is governed in the resent disclosure by the control mechanism I the overstanding'sli carry the-insulating sep lit.

ofthe-ram, extendin through slots 54, in

des 56, 57, which latter arators 58, 59, operatmg between the switch contacts 51, 52, respectively. .The switch contacts are shown as carried by long flexible s rings 60,- 61,

-ena b g quick easy action 0 the switches. These switch springs are mounted on suitable insulating su ports 62, and the contacts of the two, switc es are joined in parallel relation byconnections 63. atone side and connectiolis 64 at the. opposite side...

The circuit connections-may be'made as follows: .Z 1 I From-one side65-of the-single phase alternating current supply line to one set of the field windings, and b a cross-connection 66 to the other set 'of fie d windings,- and from the far endof said second field windinis by connection 67and bus 68' to the .leftand switch contact; the right hand switch contacts-joined by bus 64 are connected b conductor 68 with the other sideof the-A. line. This main supply circuit ma be controlled by a suitable switch indicate at 69..

Are suppressin vacuum tubes are shown at 70, 71, connecte across the line in reversed order, but both in parallel with the automatic switches. The filaments'of these tubes are shown as energized from the secondary windings 72, 73 of transformers, whose rimary windings'74, 75, are connected by wiring 76, with one side ofgthe line 65, said primaries being connected together in series by wiring 77, and by wiring 78 with the left-hand switch contacts, so that with either of the automaticswitches closed, current will flow throu h the transformer primaries, returnin to t e other side of the line across the close switch, and by way of the return connection68. The filament of tube and plat of tube 71 are shown connected with conductor 68 formin the return side ofthe line, and the plate 0 tube 70 and filament of tube 71 are shown connected by Wiring-79 with conductors 78, 77 and 76 with the oppositeside of the contactors. With this arrangement, the disb charge across the contactors at the instant of breaking circuit is taken care of by the tubes and arcing at the. switch contacts is accordingly reduced or suppressed. This are suppressor mechanism is shown only in a general way, various details being omitted, the structure being covered by a separate application" for patent.

From the foregoing, the operation will be clear, articularly by reference to Figs. 3 to 8. In igs. 3' and 6, the ram is shown just approaching the bottom of its stroke, and about to strike the anvil. At'thi s time,'the pin 53 on the ram, by engagement with the lower ends. of slots 54 and 55 has pulled both slides 56, 57 downwardly far enough to cause the upper separator 58 v to spread the upper switch-contacts 51 and the lower separator 59 diagrammatically in Fi to permit thelower switch contacts 52 to come together; Circuit through the energizing winding is thereby completed b the lower switch, and the magnetic fields s own 3 are thereby established. The resultant uxes of the primary and secondary windings at this time exert a lifting force on the ram, which is equal to the sum-of the magnetic attraction or solenoid action at the upper end of the ram and the repulsioniof the magnetic fluxes of the primary and-secondary'windings.'=As a consequeries, as the hammer its blow, it is acted on by these powerfiil electro-magnetic and electro-dynamic; forces, throwi g the ram upward on the reboundlf As the ram-in its upward travel' ap roaches and reaches a position like that s own in Fig.4, a-neutral conditionresults from the symmetrical relationofthe' parts and the symmetrical magnetic fieldsf then produced.

With current on, as by means of 'a special switch, the ram can be sustained and held in this intermediate neutral position, but with the automatic switch mechanism disclosed, the circuit is interruptedjust' before the neutral point is reached, as illustrated in Fig. 7, where both sets of switch contacts are open, and this open circuit condition continues until the ram is'about at the top of its stroke, whereupon, as shown in Fig. 8,-th e upper switch closes by the passing of separator 58 from between contacts 51, and the magnetic and dynamic reaction shown in Fig. 5 is thereby established. As shown in this view, the fluxes from'the field coils loop over the grids of the ram windings, efl'ecting a powerful downward repulsion, which in this case, also is aided by the purely magnetic or solenoid action of the lower end of the ram. In the down stroke, as in the up stroke, the circuit is interrupted before the neutral point is reached, but by the upper separator 58 opening the switch contacts 51, While switch 52 is still held open b separator 57.

By properly timing the contacts, a dynamic raking efiect mav be introduced at the top or at the bottom of the stroke, and by varying the length of contact periods, the force of the stroke in either direction may be governed to suit different requirements. By. utilizing the force of the rebound, very little energy may be used'to return the hammer, and the mainforce be put into the down stroke.

An important feature of interrupting the circuit before the neutral point is reached, is that the self-induction and counter induced electromoti've force become greatest and hence the current flow is least as the neutral position is approached, so that the circuit can be broken at such time without dangerous arcing, and such arcing as mightoccur is taken care ofin the arc suppressors above described.

present disclosure by the To prevent injury and useless expenditure of energy when the hammer is lifted off the piling or other object, the action may be automatically cut ofi as by means of a cut-off switch indicated at 80 in Fig; 6, and shown as connected by 10st motion 'nkage 81 with the anvil, so that if the anvil drops below its proper level, as it would if the hammer were lifted off the piling, the energizin circuit will be automatically interrupts This automatic cut-out, if desired, may be used as a starting and stopping switch for controllin the hammer.

As s own in Figs. 3 to5 inclusive, a complete ma etic circuit is provided for all the coils of t e stator in all positions of the ram, so that a maximum, mec anicaleffort is produced with a: minimumconsumption of ener This construction gives the machine a big startin'gpower and a generally high efliciency. The starting and operation is accomplished on-single phase current entirely without phase splitting devices, starting winding s or other accessories. The speed of opf eration is entirely independent of the frequency cit-heenergizing current, and may be made faster. or slower as required by proper use of current, and b proper timing of the. current. impulses. y varying the extent of lost motion; between the contact slides and the actuating pin on the ram, and by varying the positions of the two sets of contacts relative to each other, and relative to the ram, the timing, the force of the blows, and the cushioning effect may all be regu-.

lated as desired. The structure is simple and strong, and being substantially square in cross-section is compact, and can be used in places where operating space is quite limited. Because of the inherent efiiciency of the machine,and the fact that .the circuit is interrupted at the moments of greatest self-induction and least current flow, the drain on the line .is not excessive at any timefand the machine may be used practically on any single phase line.

B provision of special switch means to hol the circuit closed independently of the time contacts, as indicated at 83, Fig. 6, the ram may be held suspended in the neutral position shown inFig. 4, and this without excessive current, as such position is the condition of minimum current consumption. -A.

slower lift of the ram may be attained by starting the ram with the inductor bars nearer to the neutral position, that is at a point, between those shown in positions FlgS. 3 and 4. This condition may be effected by using an anvil having a higher striking face,

or by adding to the length of the hammer face i on the ram. The relatively long ram gives .weight,.and hence power with short hammer strokes. By timing the contacts to. catch the ramon the rebound, the energizing current r required to lift the ram may be quite moderetc. By closing the circuit :an appreciable time before the ram reaches'the-top "ofits. strokethe dynamicbraking efiect is utilized to cushion'the up-stroke,returning energy to the line at this time, and to start the rain back with a powerful down stroke. If desired, the maximum or an equal cushioning efiect may be introduced at the bottom stroke of the ram. The ram restson'the anvil" when the hammer is placed over the piling, and hence'the anvil determines the position of the induced current bars relative to the exciting coils at the start. The maximum starting force obtained by having'these induced current bars slightly above the center of the-stator slots, about as indicated in Fig. 3, and correspondingly the stop in the head of the hammer'determines the top stroke of the ram, the maximum power for the down stroke'being obtained by having the induced current bars of the mm at the start just below the center of the coils'as indicated in Fig. 5. The inductor' bars 01 the ram form grids, which are efiective throughout the major portions of the ram strokes, it being observed that the end grid bars alternately lose in efiicacy by passing out of the magnetic fields, only at the ends of the ram strokes.

The composite ram structure is made particularly strong and rugged by welding the and pieces thereto, and by having these welds united with the ends of the laminations and also with the. ends of the reinforcing side plates as'well'. Fig. 2 in particular shows how the welds 36 extend out over the lower ends of the-side plates at the bottom of the ram and the same feature is shown at the top 1n this view, where 37 indicates the welds uniting the cap plate tothe ends ofthe laminations and also to thefends oftheside'plates. The through bolts 33 which may be secured bybeing headed over or g riveted, serve to further unify the .structure at points intermediate the ends. The grid bars 23 may be cast or fused in place, soas to provide an absolute fit and hence eliminate any possibility of looseness. Filler pieces'are indicated at .for hold-. ing the end turns of the upper and lower coils in .place as shown in Fig. 2, and suitable wedges may be provided closing. the slots over'the windings in the manner that the coil slots are closed over the coils in the field structure ofrotary motors. The side plates 26 of themachine are shown as secured removably to the stator structure by bolts 81,

so as topermit access to the coils and to-the ram structure if the same be necessary at any time. I 4

What is. claimed is 1.. A variable speed selfstarting electric motor operable by single phase alternating current without phase splitting or special ondary starting devices, said motor comprising magnetic bodies ded one for travel in a de nite path ative to the other, a primary winding'carried by one body, a closed seccarried by the other body in inductive relation to the primary winding, and means for energizing said primary winding at such a time in the relation of said relativel movable bodiesthat them etic fluxes resu ting from the primary an secondary will react,-and by their mutual re ulsion will move the travelling magnetic y in the direction in which it is guided to travel and means for arbitrarily varying the timing of the repulsive reactions independently of the frequency of-the single phase exciting cur- 2. A variable speed self-starting single phase electric motor operable without phase splitting or other special starting devices, and comprisin magnetic bodies guided for travel in a de its path, one relative to the other, a primary winding carried by one of said bodies, a closed secondary carried by the ondary currents therein from the primary, and means for energizing the primary at a time when the secondary is oflset therefrom in such relation that the resultant primary and secondary fluxes will react repulsively to efiect movement of the magnetic body, which is free to travel in. the direction in which it is guided for movement and means for arbitrarily varying the timin of the repulsive reactions independently o the frequency of the single phase exciting current.

3. A variable speed self-starting single phase electric motor, operable without phase splitting or other special starting devices, and comprising magnetic bodies guided for travel in a definite path, one relative to the other, a single phase primary winding carried by one of said bodies, a single phase closed secondary carried by the other b6dy in position for induction of secondary currents therein from the single phase primary, and means for energizing theprimary with single phase alternating current at a time when the seconda is ofl'set therefrom in such relation that the resultant primary and secondary fluxes will react repulsively to efiect movement of the magnetic body, which is free to travel in the direction in which it is guided for movement,

a time in the continued relative movement of the magnetic bodies, while said magnetic fluxes are in the same repulsive relation.

4. An electric hammer, comprising a mageo netic ram guided for reciprocating movement,

transverse secondary conductor bars carried by said ram, stator members at opposite sides of said ram and having coil slots in the faces of the same op sed to the ram, said coil slots 6? being spaced til: same distances apart as adhavmg coil slots opposed to sai other body in position for induction of secand for interrupting the primary circuit at jom' m' g conductor bars on the ram, ;8ingl 0 phase primary circuit windings 1n said coil slots and means for controlling current in said windings for dynamically cushioning the movements of the ram.

5. A sin le phase electric hammer operating on the ynamic (principle and comprising ma etic bodies gui ed for travel in a efimte p th one relative to the other, spaced second ary conductor bars carried by one of said magnetic bodies, the other magnetic body conductor bars and spaced the same distances apoart as adjoining conductor bars on the first dy, a single phase primary winding located in said slots and means for automatically energizing said primary winding in properly timed relation of the two relativel movable bodies to effect mutual re ulsion 0 said bodies.

6. A sin 1e p ase electric hammer operating on the ynamic princi le and comprisin magnetic bodies guided or travel in a de inite ath one relltive to the other, spaced secon ary conductor bars carried by one of said magnetic bodies, the other magnetic body having coil slots opposed to said conductor bars and spaced the same distances a art as adjoining conductor bars on the first ody, a single phase primary winding located in said slots, means for automatically energizin said primary winding in properly timed refiatiun of the two relatively movable bodies to effect mutual repulsion of said bodies and including a circuit controller timed to eflect a d gag ic braking of the relatively movab e In testimony whereof I afiix m si ature.

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STILES M. 

